Re: [xml] Adding new slot in parser.h::_xmlParserCtxt

[Rob Richards <rrichards ctindustries net>]

Hi Lilith,

Lilith wrote:
> Hello,
>
> I use libxml2, libxslt, and libxml2-python. In some tasks I need to  
> redefine the default entity loader. My application runs in multithreaded  
> mode, and each thread must have a different loader . Also imported and  
> included stylesheets must be loaded with the same loader as their parent  
> stylesheet. To implement this, I did the following:
> 1) added new `loaderId' slot in libxml2::include/libxml/tree.h:_xmlDoc  
> structure;
> 2) added new `loaderId' slot in libxml2::include/libxml/parser.h:  
> _xmlParserCtxt;
> 3) modified function `xsltDocDefaultLoaderFunc' changing the type of the  
> fourth argument to `xsltStylesheetPtr ctxt' and added the following:
>                pctxt = xmlNewParserCtxt();
>         /* hacked */
>         if (ctxt) {
>                 par = ctxt->parent;
>                 loaderId = ctxt->doc->loaderId;
>                 pctxt->loaderId = doc->loaderId = (xsltStylesheet *)ctxt->doc->loaderId;
>         }
> to `xsltDocDefaultLoaderFunc' (and modified every call of this function to  
> pass the right argument);
> 4) added accessors for `loaderId' to the python wrappers in `parserCtxt'  
> and `xmlDoc' classes;
>   
If its the external entity loader you need to manage, within PHP, I use 
xmlParserInputBufferCreateFilenameDefault. Its per thread and allows me 
to take control of input handling for URIs, so we can use the PHP stream 
handlers for I/O without possible hijacking from outside sources. It is 
called by xmlNewInputFromFile and ultimately from 
xmlDefaultExternalEntityLoader. The xsl extension, as it depends on 
libxml2 ends up relying upon the custom handling as well.

Rob